Static eliminator



Aug. 2l, 1928.

H. H. RUCKEL STATIC ELIMINATOR Filed June 24, 1925 *RECEJVBR ANTENNA :FEIT

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Patented Aug. Z1, 1928.

UNITED STATES HARVEY H. RUCKEL, OF PITTSBURGH, PENNSYLVANIA.

STATC ELIMINATOR.

Application filed June 24, 1925. Serial No. 39,306.

This invention relates to radio receiving devices and pertains particularly to static eliminators.

The primary object of this invention is the provision, in a manner as hereinafter set forth, of a device adapted to be hooked up to the usual antenna and ground connections of a radio receiving tube set, and connected to the usual antenna and ground, to remove the .static or low frequency oscillations from the signals received before the signals are allowed to enter the receiving set proper.

In the eliminator embodying this invention, the first coil is the primary of the radio frequency tuned impedance. The signal enters through the antenna and thence through the first coil and a condenser, the signal circuit being closed through trie tube to a specially wound coil, or wave trap, through the positive B battery and through this battery to the tube filament and then to the ground. This is the complete "circuit, the signals travelling through the tube are reo tilied and inductively connected to secondary coil of the circuit which is connected directly to the antenna and ground connections of a receiving set.

A specially constructed variable condenser is connected between the grid and plate of the eliminator circuit which in conjunction with the specially wound coil above referred to cuts out or carries off the low frequency or static oscillations. fter the antenna and ground connections are .made between the eliminator and receiving set and the connections are made on the batteries, the filament rheostat of the eliminator is turned to about one-half on and the station is then tuned in with the receiving set. The .special condenser referred to is now adjusted until the static and interference is tuned out and if the broadcast signal is weakened the rheostat on the eliminator isl adjusted until the signals are brought back to the' proper degree of intensity.

The invention will be best understood from a consideration of the following detailed description taken in connection with the accompanying drawing forming a part of this specication, with the understanding that the invention is not confined to any strict conformity with the'showing of the drawing but may be changed and modified so long as such changes and modilications mark no material departure from the salient vductor 6 which leads features of the invention as expressed in the appended claims.

lfn the drawing F i Qjure l shows a diagram of the circuit employed in the static eliminator embodying this invention.

Figure 2 shows the primary and secondary coil employed in this eliminator, with the special coil of the eliminator associated therewith.

Figure 3 shows partly in section and partly in side elevation the special condenser used in connection with this eliminator. and,

Figure e shows an end elevation of the saine.

Referring now to the drawing in detail wherein like numerals of reference indicate corresponding parts throughout the several views, the oscillations are picked up and conveyed to the eliminator through the usual antenna indicated by the numeral l, and the antenna is connected by he wire 2 to the coil 3 .which constitutes the primary coil of this circuit and this coil is directly connected by the wire 4L to the ground 5.

Leading from the wire 2 between the antenna and the primary coil 3 is a condirectly to the grid of a vacuum tube in the' eliminator.

Connected to the wire i between the other end of the coil 8 and the ground 5 is a couductor 8 which is connected at the point 9 between the connected A and B ba tcries l0 and 1l respectively. One side of the filament 12 of the tube is also connected at this point 9 as is shown. The other side of the filament runs to the usual rhcostat 13 which is connected to the other side of the A battery l0.

Connected across betwee the conductors 6 and 8 by the conductors le is a variable plate condenser 15 of .00035 Mfd capacity.

Associated with the primary coil 3 is a secondary wound coil 18 having the conductors 1'? and 18 leading therefrom, the conductor l? being intended for connection to the antenna binding post of the receiving set in connection with which this eliminator is to be used, and the conductor 18 being intended for connection to the ground binding post of the receiving set.

In connection with the two circuits above set forth there is used a specially wound coil indicated generally by the numeral 19. One end of this coil is connected by the con ductor l2O to the vacuum tube plate 21 while the other end is connected by the conductor 22 to the positive post of the B battery 11.

Connecting across between the conductor 6 leading to the grid 7 and the conductor leading to the plate 21 is a specially constructed variable condenser 23 having a capacity of from .0001 Mlfd. to .05 lV fd. ylhe specific construction and arrangement of the coil 19 and the special condenser 23 will be set forth further in the specification.

ln the radio receiving set to which the eliminator is to be attached, a variable condenser 24 is shunted across the secondary of the last stage of audio frequency by the conductors 25 (the radio receiving set being not shown). rl`his condenser 24 is of a type having a capacity of .0001 to .05 Mfd.

ln the construction of the special coil used in connection with the eliminator, there is provided the usual tube 26 about which the primary and secondary coils 3 and 16 are wound and over these coils the special coil 19 is wound. ln the winding of these coils, a number 26 D. S. wireis preferably used, and the coils 3 and 16 are of 30 turns each wound in opposite directions in the usual manner with a space of substantially onehalf inch separating the two.

Over these two coils 3 and 16 the special coil 19 is wound and this coil has three turns to the right and three turns to the left and is four layers deep. ln starting the special coil winding, as shown in Figure 2 of the drawing, the first turnings go in opposite direction to the turnings of the coil 16 and follow the turninq's of the coil 3 and when reversed and brought back to the end of the the coil 16.

tube from whichthe start was made, the first reversed turning buck or oppose the turnings of the coil 3 and follow the turnings of r1`his method of winding the special coil is continued, going up and down the tube four times until four complete layers of wire are superimposed over the primary and secondary coils 3 and 16.

The specially' constructed condenser used in connection with this eliminator comprises three plate members of insulation, such as bakelite, hard rubber, fiberor any other suitable material, indicated by the numerals 27, 28 and 29 respectively. rlhe intermediate plate 28 has a pair of apertures 30 formed therethrough one adjacent each end thereof and through these apertures there eX- tends a metal sleeve 31, the ends of which sleeve abutt the opposing inner faces of the plates 27 and 29. Through these plates 27 and 29, and through the spacing sleeves or tubes 31, securing bolts 32 are passed which act to draw the plates 27 and 29 securely against the ends of the sleeves 31 to hold them tightly in position. rlhe member 28 is thus left slidably mounted upon the sleeves .Secured between the ends of the sleeves 31 neeiyifee and the inner face of the plate 29 are a pair of metal contacts 33 and 34 respectively separated by a layer of dielectric material 35. As shown one end only of these members 33 and 34 is secured, one beneath one sleeve and the other beneath the other sleeve 31 leaving the inner ends of the members in overlapping relation. The member 34 is of spring material and normally acts to spring upwardly away from the dielectric overlying the mem- Y ber 33.

Extending through the central portion of the plate 28 is a screw 36, the head of which is embedded in the under side of the plate as shown with the shank extending a substantial distance above the top thereof. Binding nuts 37 are threaded upon the shank and against the plate 28 to hold the screw securely in position.

Extending through the central port-ion of t-he upper plate 27 is a manipulating rod 38 the inner end of which is longitudinally bored as at 39 and threaded. This threaded bore is adapted to receive the upwardly eX- tending shank of the screw 36. about the rod 38 upon the underside of the plate 27 is an annular flange 40 which bears against the under side of the plate 27 to hold the parts in position. It will be seen that upon revolving the rod 38 the screw 36 will be fed out o-f the bore 39 or into the same as desired, to move the shiftable plate 28 in such a manner as to force the contact 34 toward the contact 33 or to allow it to move away from the same. Suitable connections may be made to the heads of the bolts 32 las indicated at 41.

As explained in the foregoing part of this specification the signal which enters through the antenna 1 is balanced by the coil 3 and the condenser 15, the signal circuit being closed through the tube to the special coil 19, through the positive post of the B battery 11, to the negative filament and then to the ground. The signal oscillations are rectified and inductively connected to the coil 16 and pass directly to the antenna and ground connections of the receiving set.

Having thus described my invention what I claim is 1. In a means for the purpose set forth an aerial, an A battery, a B battery connected together, a vacuum tube including a grid, a plate and a filament, an antenna post for a receiver, a ground post for a receiver, a primary coil connected with the aerial and the ground and having its aerial end connected to said grid and its other end 'connected to the A battery, a secondary coil connected to the antenna post and the ground post of the receiver and coupled with the primary coil, a variable condenser shunted across said primary, a reversely wound coil superimposed over said primary and secondary and having one end connected to said Formed plate and itsother end to the filament of said tube Vthrough said B battery, and a variable condenser interposed between and connected with said grid and plate.

2. In a means for the purpose set forth an aerial, an A battery, a B battery, connected together, a vacuum tube including a grid, a plate and a filament, an antenna post for a receiver, al ground post for a receiver, a primary coil connected With the aerial and the ground and having its aerial end connected to said grid and its other end connected to the A battery, a secondary coil connected to the antenna post and the ground post of the receiver and coupled with the primary coil, a variable condenser shunted across said primary, a reversely Wound coil superimposed over said primary and secondary and having one end connected to said plate and its other end to the filament of said tube through said B battery, and a variable condenser having a capacity of from .0001 to .05 Mfd interposed between and connected with said grid and plate.

In testimony whereof, I aliix my signature hereto.

HARVEY H. RUCKEL. 

